How can I find the registration for a Cathay Pacific flight made in July

Sorry, I know that this is not the correct forum for this, but i seem unable to post a new topic in any other forums.

I am curious to know if I can find the plane registration for CX170 on July 14th 2015. My brother flew on this flight that day. This is the same flight that had the engine issue last night and I was just curious to know if it was the same aircraft or not.

Thanks for any help.

Craig